This study aimed to investigate the influence of the magical first hour after birth on post-traumatic stress in traumatic childbirths. Background: Traumatic childbirth with disturbing memories can have negative impacts on the mental health of postpartum mothers. Due to the growing trend of post-traumatic stress, the emphasis of recent research is on the identification and prevention of this kind of stress and the enhancement of maternal mental health. Methods: In this randomised clinical trial, which was carried out with 84 newly delivered mothers who were diagnosed with traumatic childbirth, participants were first randomly assigned into intervention (magical first hour) and control groups. Then, the nine instinctive stages were implemented to the intervention group while the control group received routine after-birth procedures. Then, using the Impact of Event Scale-Revised (IES-R), stress was measured at three intervals of 2 weeks, 4–6 weeks and 3 months after childbirth. The collected data were analysed using a mixed analysis of variance. Results: The mean total score of post-traumatic stress in the intervention group was 16.83 ± 1.1 and in the control group 21.04 ± 1.1, which showed a statistically significant difference between the two groups (P < 0.01). With the passage of time, the average scores of post-traumatic stress in both groups decreased and no interaction was observed between time and intervention. Conclusion: Implementation of the magical hour stages is recommended as a preventive and therapeutic guideline for relieving post-traumatic stress in women with traumatic childbirth experiences.